Frequently the best mixture of two media, such as fluids and , particularly such as normally non-readily mixable fluids, such as water and gasoline or other fuel, is effected by creating substantial turbulence during the mixing process. However, to create such turbulence it often is necessary to input a substantial amount of mechanical energy to the mixing apparatus itself. Another type of conventional mixer is the motionless mixer in which typically input fluids are divided into multiple streams and the multiple streams are recombined and redivided; ultimately, of course, the streams are combined for delivery to an outlet. Frequently in the latter type of mixer the thoroughness, homogeneity, or longevity (say of an emulsion) of the mixture produced is a function of the number of streams into which the flowing fluid is split and the number of times such splitting may occur and also may be a function, in certain mixers, of the amount of turbulence actually created during the mixing process. However, the larger the number of streams into which the fluid is split or divided and the larger number of times that may occur, so will the pressure of the fluid at the outlet be reduced, and the possible turbulence imparted will require energy input again, for example in the form of effort required to pump the fluid through the mixer. Moreover, the absolute difficulty in obtaining a thorough mixture of plural fluids when the flow rate thereof is relatively small is a significant problem encountered in the past.
The use of an orifice as a fluid flow controlling and as a fluid pressure dropping mechanism is well known. A disadvantage with using an orifice to reduce fluid pressure is that the pressure drop is nonlinearly proportional to flow rate through the orifice. Also, in the past, an orifice typically was connected to a fluid line using a union type connection in which longitudinal forces clamped the orifice in place hopefully providing fluid-tight security. However, such unions are expensive, require a fair amount of labor for installation, and often do not provide the desired fluid-tight integrity of connection.